1. Field of the Invention
The present invention generally relates to a lamp, in particular, to a lamp device taking Light-Emitting Diode (LEDs) as light-emitting elements.
2. Description of Prior Art
It is no doubt that LED has become one of the products attracting most attention in recent years, thanks to its advantages of low pollution and high illumination. Besides, the light-emitting effect of an LED is uneasy to disperse, compared with that of traditional light-emitting element. Thereby, LED is not only comprehensively applied to most illuminating devices, but also applied to outdoor streetlamp recently.
Since the purpose of a streetlamp installed along a roadside is to guide people and vehicle, so its illuminating need is more severe than that of an indoor lamp. In the meantime, since of outdoor installment, LED streetlamp must be able to provide same illumination even in facing different weather conditions. In a traditional streetlamp device, a single light-emitting element is used as light source reflected by lampshade to extend its illuminating range. Even being reflected by the lampshade, the light source generated from a traditional light-emitting element is still easily dispersed, so its illuminating effect is limited, particularly, under unstable weather conditions, the illuminating effect of the streetlamp being frequently influenced by mist or rain so greatly that it becomes too vague to develop fully.
The advantage of LED can compensate the inferiority of traditional light-emitting element, besides overcoming the shortcoming of lighting dispersal, LED further being able to provide people or driver with excellently guiding effect under an awful weather, and this is a reason why LED becomes a major light-emitting element for current streetlamp device.
Although LED has the advantage of uneasy dispersal in terms of a light source, a streetlamp further needs a large range of illumination, besides a strong illumination. So, in a well-known structure of LED streetlamp, a plurality of LEDs are adopted in a formation of two rows to enhance its light-emitting illumination. In the meantime, a lampshade arranged in the lamp is cooperated to reflect and focus the light beam to augment its illuminating range.
In the aforementioned structure, although the plural LEDs are adopted as light source and its light-emitting illumination is sufficient to provide a large area of illuminating range, the light source generated from the LEDs in a formation of two rows still can not be totally reflected via the lampshade, due to a poor design of the lampshade in prior structure. In this case, the illuminating area of the lamp is unable to be extended in corresponding to the illuminating enhancement of the light source. In other words, the illuminating efficiency of the lamp is unable to be augmented in corresponding to the number increase of the light source, which on the other hand becomes a sort of resource waste. Thus, an alternative has to be sought for improving such kind of inferiority in the prior structure.